Added by on June 14, 2019 Dogs may often be confused by substitutions of one consonant for another – try saying “Fly clown” instead of “Lie down,” and your dog will probably react exactly the same. But the ability to distinguish vowels depends on rather precise analysis or the higher-pitched resonances that accompany their base pitch. Dogs do not utter vowels themselves; why should they be able to tell them apart when we say them?